/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xalan.templates;

import wx.xml.xalan.xpath.ExpressionOwner;
import wx.xml.xalan.xpath.XPathVisitor;
import wx.xml.xalan.xpath.axes.LocPathIterator;
import wx.xml.xalan.xpath.functions.FuncCurrent;
import wx.xml.xalan.xpath.functions.FuncExtFunction;
import wx.xml.xalan.xpath.functions.Function;
import wx.xml.xalan.xpath.operations.Variable;

/**
 * This class runs over a path expression that is assumed to be absolute, and
 * checks for variables and the like that may make it context dependent.
 */
public class AbsPathChecker extends XPathVisitor {
    private boolean m_isAbs = true;

    /**
     * Process the LocPathIterator to see if it contains variables
     * or functions that may make it context dependent.
     *
     * @param path LocPathIterator that is assumed to be absolute, but needs checking.
     * @return true if the path is confirmed to be absolute, false if it
     * may contain context dependencies.
     */
    public boolean checkAbsolute(LocPathIterator path) {
        m_isAbs = true;
        path.callVisitors(null, this);
        return m_isAbs;
    }

    /**
     * Visit a function.
     *
     * @param owner The owner of the expression, to which the expression can
     *              be reset if rewriting takes place.
     * @param func  The function reference object.
     * @return true if the sub expressions should be traversed.
     */
    public boolean visitFunction(ExpressionOwner owner, Function func) {
        if ((func instanceof FuncCurrent) ||
            (func instanceof FuncExtFunction))
            m_isAbs = false;
        return true;
    }

    /**
     * Visit a variable reference.
     *
     * @param owner The owner of the expression, to which the expression can
     *              be reset if rewriting takes place.
     * @param var   The variable reference object.
     * @return true if the sub expressions should be traversed.
     */
    public boolean visitVariableRef(ExpressionOwner owner, Variable var) {
        m_isAbs = false;
        return true;
    }
}

